In many surgical environments, the use of sophisticated medical procedures is either not possible, or not cost effective. For example when medical doctors in developed countries set IM nails and interlocking screws in fractured bones, the procedure is accomplished using real-time imaging (x-ray or otherwise). However, when performing this, operation in undeveloped countries, or when veterinarians set fractures in animals even in developed countries one may not have access to equipment and procedures available to the medical community in more developed countries. The present invention relates to an apparatus, and a method of using the apparatus, useful in the orthopedic repair of fractures of long bones (generally, but not exclusively, the tibia and femur) of animals. The fracture of the femur or tibia in humans resident in undeveloped countries, or the fracture of the foreleg in horses, may necessitate the use of technology that is relatively unsophisticated when compared to that used in hospitals in, for example, the United States.
The present invention comprises an apparatus that is simple to use and may be utilized by medical personnel in undeveloped countries without ready access to costly equipment that requires well-trained operators, or by surgeons concerned with the amount of radiation received by the patient and surgeon using real-time imaging. Alternatively, it may be used in more highly developed countries if the procedure does not require more highly developed technology, or in situations where (for example, on battlefields) emergency operations must be performed as quickly as possible. Additionally, there may be application of this technology by veterinarians to livestock where more costly procedures are not warranted.
The art of repair of fractured long bones has developed over decades, and for repair of serious fractures of long bones the use of IM nails and transverse screws is now well known. The screws secure the nail (when within the medullary canal) against relative axial, longitudinal and rotational movement, thereby enabling fixation of the fracture against axial, longitudinal and rotational displacement. The nails are inserted longitudinally through the medullary canal of the bone, and transverse bores must be made in the bone into which are inserted screws or pins.
The history of devices attempting to offer a dependable repeatable method for locating IM nails and securing them within the medullary canal without the aid of x-ray imaging has been largely unsuccessful. The primary problem has been the orientation of the IM nail, and the securing slots therein, as they are affected by the internal shape of each patient's individual medullary canal. The present invention provides an accurate and reproducible apparatus and method for locating the IM nail apertures even when the nail has been deflected within the bone.
Prior art devices have attempted the correct positioning of the transverse bores by, for example, the device disclosed in U.S. Pat. No. 4,976,258. A fitting is adapted to hold a telescopic guide member which engages the window of an image converter or the front portion of the housing of an X-ray source such that the axis of the guide member is coaxial with the X-ray beam axis, thereby assuring proper alignment of the axial bores with apertures in the nail.
U.S. Pat. No. 4,848,327, Perdue, discloses a method of emplacing an orthopedic nail into the IM area of a long bone, using a fluoroscope assembly to develop an image on a monitor. This image enables a physician to adjust the fluoroscope assembly until the X-rays from the fluoroscope are coaxially aligned with nail screw holes in the nail, thereby ensuring that the screws are properly aligned.
Another method of attempting to accomplish the same result is illustrated in U.S. Pat. No. 5,478,343, Ritter. This patent discloses a targeting device for making holes in cortical bone for bone nails. An X-ray machine is used to maintain the drill in position during drilling, with an aligned telescopic guide then used to complete the drilling operation.
U.S. Pat. No. 5,584,838, Rona, et al. discloses a method of aligning a drill for drilling transverse holes in bones. A magnetic field with maximum strength along an axis of a transverse hole decreases in strength in directions radially away from the axis. Sensors are provided at axially spaced locations on a drill guide detect deviation of the drill guide. An X-ray machine emits radiation along a longitudinal axis and an X-ray collector is used in conjunction with a visible laser light in U.S. Pat. No. 5,031,203, Trecha. A target grid member is disposed on the X-ray collector portion for targeting the visible laser light in coaxial relationship with the axis of the X-ray radiation gun. U.S. Pat. No. 4,969,889 Greig discloses an instrument for locating apertures in an IM nail. A guide sleeve is substantially translucent when subjected to X-ray visualization, and a pin is opaque so that the pin can be aligned with the hole of the IM nail.
The invention of U.S. Pat. No. 4,667,664, Taylor et al. comprises a method of installing an implanted orthopedic IM nail in the medulla of a fractured long bone. The inventive device is intended to locate the blind screw holes in the end of the nail, so that screws can be quickly and accurately be emplaced to secure the nail within the bone. A target mechanism is aligned using a standard X-ray device, and is arranged so that it can be moved in four degrees of movement, thereby facilitating precise coaxial alignment with blind screw holes in the nail. Finally, U.S. Pat. No. 6,093,192 discloses a device for proximal and distal locking of IM nails without X-rays.